Jyubnace



w; NN. DUNCAN.

FURNACE.

APPLICATION FILED nwe. 1915.

RENEWED MAY 8A HMS.

Pueutcd Decfl, 1910.

ETI.

avv.

W. M. DUNCAN.

` FURNACE.

APPLICATION FILED DEC-5, |915.

RENEWED MAY 8.1919.

Patented Dec. 1G, 1919.

3 SHEETSvSHEET 2.

@lim W. IVI; DUNCAN.

FURNACE.

APPLICATION FILED D506, I9I5. `IIEIIEWEIJ MAY 8. |919.

Patented Dec. 16, 1919.

WHA/raf@ M zaz cazz,

UNITED STATES wLLIAM M. DUNCAN, or ALToN,.ILLINoIs.

FURNACE.

Specification o'f Letters Patent. y Patented De, i6, 1919.

Application led December 6, 191'5, Serial No. 65,247. Renewed May y8, 1919. Serial :No/295,700.

To all whom z't may concern: Beit known that I, IVILLIAM M. DUNCAN, a citizen of the UnitedStates of America, residing at Alton, in -the county of Madison, State of Illinois, have invented certain new and useful Improvements in Furnaces, of which the following is a full, clear, and eiiact description, reference'being had to the accompan ing drawings, forming a part of thisspeci cation.

My invention rela'tes to a furnaceequipped with a mechanical stoker and yother *elements `'adapted to be associated therewith toprovide forvthe combustion of Vanthracite coalona traveling grate.. Under some conditions, 'where anthracite coal is the most desirable fuel, and in some localities where such coal is not too expensive,

thereis a :marked demand for mechanical stokerscapable of handling anthracite coal,

,and attempts have, therefore, been made to burn coal of this kind'onk traveling chain {grates 'Howeven the Various conditions essential to the ignition and combustion of anthracite coal are quite different from the conditions necessary in burning bituminous coal, and theV desired new conditions ca-nnot 'be obtained in the Aordinary mechanical stokers.

The preferred form of the present invention comprises means for supplying anthracite coal to a traveling grate at two different points, the ate bei-ng adapted to carry coal from one ogfTsaid points to the other. The

` object in supplying'coal at two points, in-

stead of delivering all of the coal to the grate at one point, is to facilitate the ignition and combustion of the coal. The new structure preferably includes two coal re- 40 ceptaclcs, from which the coal is discharged onto the grate at two different poi-nts, and, for the sake of convenience in describing,` the invention, I will term one of these receptacles a primary coal receptacle and the other a Secondary coal receptacle. The comparatively thin bed of anthracite coal passing from the primary receptacle will ignite an' burn more readily than a larger body of 'anthracite coal, and the parts of the new apparatus are so constructed and ar'- ranged that, this comparativclyithin bed of coal will be Fully ignited before it reaches the point at which the green coal is dischar ed from the secondary coal receptacle. 56 :Ehe ody of coal traveling from one of the discharge points to the othei` is4 pref-A erably subjected to the actionl of 'an'induced draft, whereby flame and hot gases 1n the fire-box are drawn toward this com parat1vely thin body of coal, thus providing for the ignition and combustion of the coal near the prlr'nary discharge point. Before this body of coal reaches the 'secondary discharge point, it is preferably subjected to.

the action of Va forced draft so that the green coal dropping onto the burning coal will be readily ignited at or near the secondary dis, charge point.k

With the foregoig and other objects view the invention comprises thenovel construction, combrnatlon and arrangement of parts hereinafter more specifically described and illustrated in the accompanying drawings wherein is shown thel preferred embodi ment of the invention; however, it is to 'ne understood thatthe invention comprehends changes, variations and modifications which come within the scope of the claims hereunto appended.

Figure I isa longitudinal section of a furtion.

Fig. II is a top or plan view illustrating nace, embodying the features of -my invenv the endless fuel carriers and the draft apy plian'ce associated therewith, some of the elements of the draft appliance being shown diagrammatically.

Figa-III is. an enlarged vertical section I taken approximately on the line III-III',

Fig. I.

Fig. IV is an enlarged detail Viewv showjing a portion'of the bottom .wall of one of the draft-boxes and the closures fitted to 'said bottom wall,

Fig. V is a section on line V-V, Fig. IV. 1 designates the side walls of afurnace-` and 2 designates tracks located between said side walls. Side frames 3 and 4 are provided with wheels which rest upon the tracks 0 A drive shaft 5, mounted in the side frames at the front of the grate, is provided with a series of sprocket wheels 6 which lie l.

between the side frames ol and 4. An idle shaft 7 at the rear of the grate is provided with idle wheels 8. The wheels 6 and 8 constitute supporting elements for a series of traveling fuel carriers, and leach ofthese fuel carriers comprises an endless sprocket chain 9 fitted to one of the sprocket wheels 6 at the front of the grate and also fitted to y-ifd'lc \\`heel"8 at the rear of the grate. 1a

'cli fuel supporting unit 1sY a rectangular' having' pcrfol'at'ionsfor the admission of air to the' fuel', andprovided with 5f-legs which ,are secured tothe pivot pins forming part of the endless chain structure. "Ther-fuel supporting members '10 lap each other', asshown in Figs, I and-III.

. u -ZIhedraft-appliance comprises-'manifolds. 1,0.'l2, '13,14 and 15, arranged.'transversely of the fcha'in grate' structure, and secured 'at -their ends to the side frames 3 and 1. Presi, frsurefpip'e's v1G, passingA through afurnace wall 1, arefittedto the manifolds .13, 14

regulating. the .flQw'of air through the mani- `folds.- Each valve '17 is adapted-to control the'fllaft in'only one of th'efmanifolds, and thesevalves maybe adj usted independently 5:20 of-each other-'to vary the draft at different parts .of tlurfuelv bed. A suction pipe 18, lis littedgto 'the'manifold 12, las -shown in Fig'SJII and IIL The suction pipe 18 leads to the intalcelopening 'offiz blower', or blast 25 device 19, 'the'la'tter' being lshown diagram- '40;tl1e. grate, comm'unicates with draft boxes .22' and 22',- the boxes 22 lbeing located at the-sides of the grate; as shown in Figs. Il ,and III, and the 'draftvboxes 22 beiner lo.- 'catedb'etween said draft` boxes 22.'y "ach draft boal isclosed atits sides-and ends, and

' 4".open attheitop to 4permit the gases to cir- ."culate'through thev perforations in the .fuelv ,supportingmembers 10. The different dra ft iboXes are separated from each 'other-to provide passagewaysfor the endless sprocket '.chainswhich 'travel bet-Ween said draft boxes#4 Draft ,boxes 23 and 23T., located adjacent tothe draft boxes 22- and 22', are provided 'efwi'thend )valls 2,4 and bottom-and side-Walls connectingsaid end walls.4 All of these draft boxes 23 and 23 arein comn'iunication with the manifold 13, and ,they are sepan ated from each other to permit the sprocket .60l chains to-pass between then'r.' Draft boxes 25 and 25 are open at the top and provided with side, endand bottom Walls, said draft boxeslbeing in communication with the manifold .14. 26 and 2G designate rear draft boxes abutting `against the draft-.boxes any ofthe other draft boxes.4

25 and 25', respectively, said rear draft boxes being in conununication with the l manifold 15. I

The draftboxes -are connected to ether to form several longitudinal rows of oXes, `l but the draft boxes 22 and 22 near the front of the grate, are not in communication with In other words, each series ofdraft boxes is are ranged transverselyofthe grate so as to communicate with only one of Athe mani-f folds 12, 13, le or 15. lVhen the blower 19 is in operation, an' induced draftA is created in the draft boxes 22 and 22', a forceddraft bcingvcreated in the other-draft boxes. Hot 8Ol A gases generated 'in the fire-box are drawn downwardly through the grate at a point above the draft boxes 22 and 22'.. These .gases flow through.themanifold 12, suction pipe 1S, blower-19, discharge pipe 20,pres- 85 sure pipes 16, into the manifolds 1 3, 14 and 15, through the draft boxes 23', 25 and 26 and then to thefuel Which lies immediately above the lasthlentioneddraft boXes.,Theg

Y, combustible gases circulating from' the fre- 90?A i box in response to the action ofthe induced draft, are returned in 'responsefto"theaction, 'ofthe forced draft. 'y

- 30 designates tracks arranged in the upper portionsof thedraft boxes to receive the lapped Amarginal portions of'the fuel supporting members 10. 'Guif'le-members 31, extending forwardly from the front ends Iofthedraft boxes 22, areiadapted to guide the fuel supporting members onto the draft i boxes. A

Dlscharge openings 32 are formed inthe bottom ofeach draft box, said discharge t openings being normally closed by doors or closures. 33.' The closures 33 in eachlongi- 105 tudinal row of draft boxes are secured t0- gether by a connecting-'bar 34, so that all of the closures may be operated at'the same time. The means for operating the closures comprises a rock shaft 35 lia-vingl a series-of` 110 arms 3G, the upper ends of said'arms being I secured to the closures 33 near the front of the grate. The. means for actuating the iock shaft 35 comprises an arm 37 secured to one end-Of said, rock shaft, and an oper- S115 ating rod 38 connected to said arm. When the grate is in service, ash, etc. will drop throughthe perforations in the fuel supporting members and fall onto the bottom Walls of the draft boxes 23, 25 and 26'. Such 120 material may be readily blown through the discharge openings 32 by opening -all of the closures 33.\vhen air under-pressure is owingthrough the manifolds 13, 14 and 15'. i

grate is in service .the coal travels from said receptacle toward the rear of the furnace, as indicated by arrows in Fig. I. A secondary coal receptacle 41, located above the grate, is provided with a discharge opening 42 through which coal may be discharged as indicated by arrows inFig. I. 43 designates a rotary feeder arranged in the bottom of the secondary coal receptacle 41, and provided with a sprocket wheel 44 which lies at the exterior of said coal receptacle. A drive chain 45', passing around the sprocket wheel 44, is fitted to a drive wheel 46, the latter being secured 'to the drive shaft 5. 4T designates an adjustable gate located near the bottom of the coal receptacle 4l to control the flow of coal to the feeder 43. l

It is importantto note that the coal is discharged onto the traveling grate at two different points, the path of the coal being indicated by the arrows shown by full lines in Fig. I, and the directions of the draft ,being indicated by dotted lines. The induced draft boxes 22 are located near the discharge end of the primary coal receptacle 4t), so that the flame and hot gases will be drawn onto the. coal at a point adjacent to said primary coal receptacle. the object being to ignite this comparatively thin body of coal before it reaches the point at which the coal is delivered from the secondary coal receptacle.` The hot gases flowing to the draft boxes 22, are drawn in a direct-ion opposed to the direction in which the fuel travels. An ignition arch, consisting vof a series of heat radiating blocks 50, is preferably located above the grat-e in a planche-` tween the two points at which coal is delivered to the `grate.

When the coal passing from the primary coal rccelitacle 40 reaches the plane of the draft boxes 23. it is subjected to theI action of the forced draft flowing from said draft- `boxcs. and thereafter the cdal )assiner from P9 the secondary receptacle 4l is discharged onto the. burningcoal when the latter is sub- `ected to the action of the forced draft. 'lhe green coal discharged at the last mentioned point will readily ignite as it travels with the burning coal, the draft being upwardly so as to insure the, desired ignition and combustion. y

'lhe combination of draft boxes and fuel carriers, arranged as herein disclosed. is claimed in an application for patent filed ,bv me November 20. 1915. Serial No. (32,507,

furnaces, renewed May 8. 1919, Serial No. 295,699.

I claim:-

l. In a furnace, the combination with a fire-box provided with a travelinglr grate, of

draft producing means providing for an i a traveling grate, means for supplyingfuel to said grate, andmeans for creating an 1nduced draft in said lire-box in a direction conti-ar f. to` the direction of movement of said grate and then downwardly through the fuelon the grate.

3. In a furnace, the combination with a hre-box provided with a travelling grate, of

draft producing means providing for a con-l tinuous 11p-draft through the grate at onel point, then in a di'rectlon contrary to the direction of movement of the'grate, then downwardly through the back to the point at which the draftcirst passes through the grate.

4. In a furnace, a tire-box provided with a traveling grate, means for supplying fuel to said grate at two different points, one inadvance ofthe other relative to the direction of movement of the grate, and a draft appliance for creating an induced draft in said tirc-box in'a direction contrary to the direction of movement of said grate and then downwardly through the fuel on the grate between the two points at which the coal is delivered to the grate.

5. In a furnace, a tire-box provided with a traveling grate, means for supplying coal to said grate at two different points, one in advance of the other relatife tothe direction of movement of said grate, and means .y

for creating a forced draft through one p0rtlonA of said grate and an lnduced draft through another portion of said grate, said Y, In a furnace, a tire-box provided with a traveling grate. means for supplying fuel to said grate at two different points, one in advance of the other relative to the direction of movement of said grate, and a draft pro ducing means for ,creating a force-d up-diiaft through tbe grate adjacent the advance/ fuel supply p )int and an induced down-draft through the portion ofthe grate between the two points of supply ollfifuel to the grate.

7. In a furnace, a tire-box provided with a traveling grate, means for supplying fuel to said' grate at two different points, one in advance of the other relative to the direction of movement of the grate, and means for creating both an induced down draft and a forced up-draft through said grate between the points at wvhich the fuel is delivered thereto.

f V.W'ILLIAltI M. DUNCAN.

grate, and then downwardly through Y 

